This invention provides a monitoring device which will initiate an alarm or provide an orderly shut-down of equipment in the presence of excessive vibration.
Moving equipment, most notably that which is powered by a rotating shaft, may be subjected to severe and dangerous vibrations in the event of unbalanced operation. An unbalanced condition may occur if the driven load becomes unequally distributed, or as a result of of a failure within the moving equipment itself.
In the normal course of operation, all equipment driven by a rotating shaft will have inherent vibration qualities. In general, the vibration frequency is a function of the rotational speed of a given shaft, whereas the amplitude is a function of the amount of imbalance. Equipment using rotating shafts will, therefore, have a design limit of tolerable vibration. However, if that limit is exceeded, some provision must be made to rectify the condition.
Monitoring vibration, therefore, has a twofold purpose: The first purpose is in providing safety for personnel operating the equipment. The second purpose is to minimize damage to the equipment by a timely shut-down of the machinery if excessive vibration occurs. It should therefore be obvious that an automatic means of disengaging the motor or prime mover (or of sounding an alarm) is generally preferable to a manual shut-down procedure performed by an operator.